Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756929AbaBFWUx (ORCPT ); Thu, 6 Feb 2014 17:20:53 -0500 Received: from smtp.outflux.net ([198.145.64.163]:57579 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751296AbaBFWUw (ORCPT ); Thu, 6 Feb 2014 17:20:52 -0500 Date: Thu, 6 Feb 2014 14:20:02 -0800 From: Kees Cook To: =?iso-8859-1?Q?J=F6rn?= Engel Cc: "Theodore Ts'o" , "H. Peter Anvin" , Linux Kernel Developers List , macro@linux-mips.org, ralf@linux-mips.org, dave.taht@gmail.com, blogic@openwrt.org, andrewmcgr@gmail.com, smueller@chronox.de, geert@linux-m68k.org, tg@mirbsd.de Subject: Re: [PATCH,RFC] random: collect cpu randomness Message-ID: <20140206222002.GC23300@outflux.net> References: <20140202203617.GA9499@logfs.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20140202203617.GA9499@logfs.org> Organization: Outflux X-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi J?rn, On Sun, Feb 02, 2014 at 03:36:17PM -0500, J?rn Engel wrote: > Collects entropy from random behaviour all modern cpus exhibit. The > scheduler and slab allocator are instrumented for this purpose. How > much randomness can be gathered is clearly hardware-dependent and hard > to estimate. Therefore the entropy estimate is zero, but random bits > still get mixed into the pools. Have you seen this work from PaX Team? http://grsecurity.net/pipermail/grsecurity/2012-July/001093.html See http://grsecurity.net/test/grsecurity-3.0-3.13.1-201402052349.patch and search for PAX_LATENT_ENTROPY. -Kees -- Kees Cook @outflux.net -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/